Definition
The 'genus Ulmus' is a group of trees known as elms. These trees belong to the Ulmaceae family and are known for their asymmetrical leaves and winged fruits called samaras. They're common in temperate climates and have been valued for timber and shade. The American elm (*Ulmus americana*) was once a popular street tree but has been devastated by Dutch elm disease. It is also a common ornamental tree.